[vim] Update FZF command not set up lengthy prompt on narrow screen
[vim] Update FZF command not set up lengthy prompt on narrow screen

Port of https://github.com/junegunn/fzf.vim/commit/e7928d154aad71e530daf5c17733275da5732680

Since :FZF does not enable preview window, we determine based on full
&columns instead of &columns / 2.

junegunn/fzf,wilywampa/fzf,wilywampa/fzf,janlazo/fzf,infokiller/fzf,stuha/wbr-zsh,infokiller/fzf,junegunn/fzf,janlazo/fzf,infokiller/fzf,wilywampa/fzf,janlazo/fzf,junegunn/fzf